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Title: Dielectric collapse at the LaAlO 3/SrTiO 3 (001) heterointerface under applied electric field

The fascinating interfacial transport properties at the LaAlO 3/SrTiO 3 heterointerface have led to intense investigations of this oxide system. Exploiting the large dielectric constant of SrTiO 3 at low temperatures, tunability in the interfacial conductivity over a wide range has been demonstrated using a back-gate device geometry. In order to understand the effect of back-gating, it is crucial to assess the interface band structure and its evolution with external bias. In this study, we report measurements of the gate-bias dependent interface band alignment, especially the confining potential profile, at the conducting LaAlO 3/SrTiO 3 (001) heterointerface using soft and hard x-ray photoemission spectroscopy in conjunction with detailed model simulations. Depth-profiling analysis incorporating the electric field dependent dielectric constant in SrTiO 3 reveals that a significant potential drop on the SrTiO 3 side of the interface occurs within ~2 nm of the interface under negative gate-bias. These results demonstrate gate control of the collapse of the dielectric permittivity at the interface, and explain the dramatic loss of electron mobility with back-gate depletion.
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [3] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7]
  1. SLAC National Accelerator Lab., Menlo Park, CA (United States)
  2. Stanford Univ., CA (United States). Geballe Lab. for Advanced Materials
  3. SLAC National Accelerator Lab., Menlo Park, CA (United States); Univ. of Tokyo (Japan)
  4. High Energy Accelerator Research Organization (KEK), Tsukuba (Japan)
  5. Univ. of Tokyo (Japan)
  6. Japan Synchrotron Radiation Research Inst. (JASRI), Sayo (Japan)
  7. SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., CA (United States). Geballe Lab. for Advanced Materials
Publication Date:
Grant/Contract Number:
AC02-76SF00515
Type:
Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 7; Journal Issue: 1; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE
OSTI Identifier:
1390591